Electrical condenser



March 8, 1932. 5 s CRAMER 1,848,872

ELECTRICAL CONDENSER Filed April 25, 1930 y 1 J g2 awucutoz STANLEY S. CRHMER Patented Mar. 8, 1932 UNITED STATES STANLEY S. CRAHER, OF HADDON HEIGHTS, NEW JERSFFY, ASSIGNOR '1'0 RADIO CON- DENSER COMPANY, 013 CAMDEN, NEW JERSEY ELECTRICAL CONDENSER Application filed April 23,

This invention relates to improvements in the construction of variable electrical condensers such as are ordinarily used in radio receiving sets.

In the design of such condensers, it is qulte customary at the present time to-arrange a plurality of the tuning condensers on a single framework into what is termed a gang condenser, so that one shaft andone dial operate all of the rotors or movable groups of plates simultaneously.

In order to slightly change the capacity of each and every condenser of the gang, it has become quite common practice to use small auxiliary or trimming condensers with each one of the main condensers so as to com ensate for variations in the construction 0 the main condensers and capacity of the wiring, etc.

In my application, S. N. 332,700, filed J anuary 15, 1929, I have shown and described a gang condenser. A certain construction of these auxiliary condensers is utilized, but in said application the adjustment of the auxiliary condenser is made by adjusting one of the plates comprising the auxiliary condenser y means operable from the side of the condenser. Where the gang condenser is mounted in a cabinet, it is frequently found that this side adjustment is not convenient to get at, and one of the objects of 'm present invention is to improve the method of mounting and adjusting the auxiliary condenser which overcomes these difficulties.

Another object of my invention is to provide a frame for the condenser that is cheap to manufacture and one which will allow the main and auxiliary condensers to be mounted in a very expeditious manner.

Another object of my invention is to provide a shield and brace plates which not only act to shield the main condensers comprising thel gang, but the auxiliary condensers as wel In carrying out my improvements, I have chosen to illustrate the same in connection with a. three-gang condenser in which the rotors are carried on a shaft supported in the manner described in my application previously referred to. In order to show the de- 1930. Serial No. 446,437.

tails of my present improvements, the drawings have been made somewhat skeleton in form;

Figure 1 being a plan view of a three-gang condenser showing one group of stationary and variable plates connected to the shaft, and an auxiliary condenser with a slight modification is shown for operation with a second main condenser, the plates of which are not shown.

Figure 2 is a side elevation of Figure 1.

Figure 3 is a half section on the line 3-3 of Figure 2.

Figure 4 is a fragmentary view looking from the bottom of the frame, including two of the brace and shield lates showing the auxiliary condenser there etween.

In the drawings, wherein like numbers refer to corresponding parts in the various views, 1 is the bottom part of the frame of a condenser, which is preferably made of sheet metal, with upturned sides 2 and 3. The sides 2 and 3 at the ends are provided with projections 4, while the bottom has at least one projection 5 at each end. These projections are used for attaching end support members 6 thereto, it being understood that the end plates are provided with holes to receive the projections 4 and 5 which are upset after the ends are placed in position. The end support members 6 carry a rotor shaft 7 mounted on ball bearings supported in the recess 8,1111 as shown and described in my application previously referred to.

Supported on the rotor shaft 7, are hubs 9, each carrying a group of rotor plates 10. Each side 2 and 3 ofthe frame is provided with a plurality of openings 11, and from the bottom 1, at each of the openings 11, are upturned lugs 12 which are arranged in planes on Opposite sides of the bottom 1 substantially parallel with the sides 2 and 3, but spaced inwardly therefrom, as clearly shown in Figure 1.

The lugs 12 are provided with holes 13 for mounting the insulators 14. The insulators 14 may be mounted on the lugs 12 by screws, but I prefer to use rivets 15, passing through the outside holes 13 and riveting them on the inside of the lugs 12. The insulators 14 are provided with holes 16 through which pass screws 17 that engage tie bars 18, which in turn carry the stator groups of plates 19. It will thus be seen that each group of stator plates over each main condenser is fastened to the frame through a pair of insulators 14; in the manner just described.

Mounted on the insulators on at least one side of the gang condenser, is an auxiliary or trimming condenser composed of two metallic members, which in the form shown, are generally L-shaped, being mounted in reverse position one with respect to the other. The lower member, which is in the'form of a bracket 20, is mechanically and electrically connected to the frame by means of a screw 21 passing through the insulator 14 into the central hole 13 in the lug 12, this hole being tapped to receive a screw. The bracket 20 has a lug 22 turned over the lower edge of the insulator 14: so as to prevent the bracket 20 from turning on the insulator. The other element of the auxiliary condenser is the member 23 fastened to the insulator 14.- by screw 24 which also enters the tie bar 18 of the stator group of plates. To at least prevent the auxiliary condenser elements 20 and 23 from touching, an insulator 25, preferably of mica, is placed between these plates and insulating bushing 26 is used to insulate the adjusting screw 27 from the condenser plate 23, it being understood that the screw 27 is screwed into the condenser bracket element 20 whereby the distance between the plates 23 and 20 may be adjusted. It will be noted that the auxiliary condenser elements 20 and 23 extend outwardly substantially at right angles to the insulator 14 and the screw 27 is so positioned that it may be adjusted by a tool, such as a screw driver, from the top of the condenser, or in a plane substantially parallel to the sides of the frame. This manner of arranging the auxiliary condensers makes it a decided improvement over the arrangement shown in my application previously referred to.

The plate 23 is provided with an integral terminal 28 by which electrical connection may be made with the stationary group of plates of each main condenser. In the righthand main condenser of the gang, the termi nal 28 is shown-in a somewhat different form than that shown with the central main condenser, indicating that this terminal may be arranged on the plate 23 in any suitable manher.

I have arranged between each of the main condensers, a combined shield and brace plate 29 which is more clearly shown in Figure 3. The plate 29 is provided with slots 30 adjacent each end which are adapted to fit over the sides 2 and 3 of the frame, and the metal 31 at the inner end of the slot 30 engages notches 33 in the upper edges of the sides of the frame. The plates 29 are also provided with projections 32 which engage corresponding holes in the bottom 1, after which the projections 32 are upset so as to hold the plates 29 in position. As will be seen by reference to Figures 1 and 3, the shield and brace plates 29 extend a considerable distance above the upper edges of the sides 2 and 3, and also may overlap these sides and extend a distance beyond the sides so as to act as shields for the auxiliary condenser. While l have shown the auxiliary condensers mounted on only one side of the gang condenser; that is, one auxiliary condenser for each main condenser, the opposite side of the gang may be likewise equipped with such auxiliary condensers.

In some cases, the gang condenser may be mounted in an inverted position from that shown in Figures land 2, and when so mounted, the end of the screws 27 is slotted as indicated at 33 so a screw driver may be used as before to adjust the screw and the capacity of the auxiliary condenser. Preferably the entire condenser structure is fitted with a metal shield cover as indicated by the dotted lines 34 in Figures 1 and 2. lVhen the cover 3 1 is used, it is preferably provided with grooves 35 which fit the ends of plates 29, and the cover ends are slotted to fit over the shaft end or ends, the bottom of the slots resting against the parts forming the ball recesses. It is to be understood that the depth of the cover is such as to provide suflicient clearance for the rotor plates as they are turned by the shaft 7. Thus, each condenser of the gang is shielded from the next adjacent one and the whole is shielded from other apparatus.

From what has been said, it will be seen that the details of my invention may be varied without departing from the spirit of the invention or the scope of the appended claims.

Having thus described my invention, what I claim is:

1. An electrical condenser having a frame with end support members, a shaft journaled in said support members, a transverse section through the frame being generally U- shaped, a plurality of spaced openings opp0- sitely disposed in the sides of the frame, a lug upturned from the bottom of the frame on one side of each of said openings, an

insulator for each lug having one end fastened to its lug, groups of stator plates positioned in the frame between pairs of said lugs, each group being fastened to the other end of the insulators carried by said pairs of lugs, rotor groups of plates carried on said shaft for cooperation with said stator groups to form main condensers, an L-shaped bracket mounted on one of theinsulators of each main-condenser but connected to the frame forming one element of an auxiliary condenser, and a second element of said auxiliary condenser insulated from but mounted for cooperation with said oracket so as to be adjusted by a tool held in a vertical plane, each of said auxiliary condensers being connected across its associated main condenser, a shield and brace plate carried by the frame between each main condenser and extending a distance from opposite sides of the frame.

2. An electrical condenser having a frame with end support members, a shaft j ournaled in said support members, a transverse section through the frame being generally U- shaped, a plurality of spaced openings oppositely disposed in the sides ofthe frame, a lug upturned from the bottom of the frame on one side of each of said openings, said lugs being located in planes within the sides of the frame and substantially parallel thereto, an insulator for each lug having one end fastened to its lug and extending upwardly therefrom, groups of stator plates positioned in the frame between said lugs, each group being fastened to the other. end of pairs of said insulators, rotor groups ofplates carried on said shaft for cooperation with said stator groups to form main condensers, an L-shaped bracket mounted on at least one of the insulators of each main condenser but connected to the frame, a metal member car- 'in the frame between said lugs,

ried on said insulator and separated from the bracket by an insulator and adjustable with respect to the bracket 'by means operable from the top of the condenser frame,

said bracket and metal member acting as an auxiliary condenser and being connected across its associated main condenser, a shield and brace plate carried by the frame be: tween each main condenser and extending on at least one side of the frame where the auxiliary condenser is located, so as to shield them, one from the other.

3. An electrical condenser having a frame with end support members, a shaft journaled in said support members, a transverse section through the frame being generally U- shaped, a plurality of spaced openings oppositely disposed in the sides of the frame, a lug upturned from the bottom of the frame on one side of each of said openings, said lugs being located in planes within the the frame and substantially parallel thereto; an insulator for each lug having one end fastened to its lug and extending upwardly therefrom, groups of stator plates positioned each group being fastened to the other end of pairs of said insulators, rotor groups of plates carried on said shaft for cooperation with said stator groups to form main condensers, an L-shaped bracket mounted on at least one of the insulators of each main condenser but connected to the frame, and means for preventing the bracket from turning on the insulator, a

spring plate attached to the insulator andelectrically connected to its associated stator sides of group, said plate and bracket formin an auxiliary condenser, a screw insulated rom but passing through the plate into the bracket for, adjusting the position of the plate, said screw being adjustable by a tool held in a vertical position, a shield and brace plate carried by the frame between each main condenser and extending on at least one side of the frame where the auxiliary condenser is located, so as to shield them, one from the other.

4. An electrical condenser having a frame with end support members, a shaft j ournaled in said support members, a transverse section through the frame being generally U-shaped, a plurality of spaced openings oppositely disposed in the sides of the frame, a lug upturned from the bottom of the frame on one side of each of said openings, said lugs being located in planes within the sides of the frame and substantially parallel thereto, an insulator foreach lug having one end fastened to its lug and extending upwardly therefrom, groups of stator plates positioned in the frame between said lugs, each group being fastened to the other end of pairs of said insulators, rotor groups of plates carried on said shaft for cooperation with said stator groups to form main condensers, an auxiliary condenser comprising; two L- shaped metal members mountedon at least one of the insulators supporting each main condenser in inverse position and having their free portions extending outwardly, one over the other, from the insulator, an insulator'separating said for adjusting said free portions one with respect to the other, said adjusting means bein operable by a tool held substantially vert1- cally along the side of the frame, each auxiliary condenser member being connected across its associated main condenser, shield and brace members carried by the frame between each ma'in condenser.

5. An electrical condenser having a frame with end support members, a shaft j ournaled in said support members,-a transverse section through the frame being generally U- shaped, a plurality of spaced openings oppositely disposed in the sides of the frame, a lug upturned from the bottom of the frame free portions, means on one side of each of said openings, said I auxiliary condenser comprising; two metal members adjacently mounted on at least one .Of the insulators supporting eachmain conwardly away from the sides of the frame,

means for adjusting one of said two members with respect to the other, an insulator between the two members to at least prevent plates.

short circuiting them, said adjusting means being operable bya tool held substantially F in a vertical position, shield and brace members carried by the frame between each main condenser and lapping over the sides of the frame and extending a distance from the sides substantially equal to the extended length of said auxiliary condenser members.

6. A variable condenser including; a frame having a bottom and upturned sides and end support members, a shaft carried by said end support members, groups of rotor plates carried on said shaft, said sides having oppositely arranged openings therein,. lugs turned up from the bottom on one edge of said openings, supporting tie bars, stator plates to cooperate with said rotor plates to form main condensers secured to said bars, insulators connecting said bars to said lugs, said insulators being secured at one end to said lugs and extending upwardly within the projection of said openings and connected at the other end to said supporting tie bars, at least one auxiliary trimming condenser for each main condenser mounted on said insulators and composed of at least two parts, one adjustable with respect to the other, said ad justment being efi'ected bya tool held in a vertical plane, and shield and brace plates between each main condenser and extending above'the edges and beyond the sides of the frame to form pockets for the auxiliary condensers.

'i'. For a gang condenser, a frame consist ing of; a piece of sheet metal having a plurality of oppositely spaced openings punched therein and lugs turned upwardly at the inner edges of said openings, sides turned upwardlyin planes adjacent and outside the lugs and parallel thereto, said openings being in said sides, end plates for supporting a shaft which carries groups of rotor plates, said lugs serving to support stator groups of plates, combined shield and brace plates positioned between pairs of said openings and a metal cover fitting over the entire frame, being positioned on the end of said shield 8. For a gang condenser, a frame consisting of; a piece of sheet metal having a plurality of oppositely spaced openings punched therein-and lugs turned upwardly at the inner edges of said openings, sides turned upwardly in planes adjacent and outside the lugs and parallel thereto, said openings being in said sides, end plates for supporting a shaft which carries groups of rotor plates, said lugs serving to support stator groups of plates, said sideshaving oppositely arranged notches at their edges between said openings, combinedv shield-and brace plates having a slot near each end to slip over said sides and engage said notches, lugs on said brace plates to engage the bottom of the frame and a metal cover fitting over the en tire frame, being positioned on the end of said shield plates.

9..For a gang condenser, a frame consist-i ing of; a piece of sheet metal having a plurality of oppositely spaced openings punched therein and lugs turned upwardly at the inner edges of said openings, sides turned upwardly in planes adjacent and outside the lugs-and parallel thereto, said openingsbeing in said sides, end plates for supporting a shaft which carries groups of rotor plates, said lugs serving to support stator groups of plates, and combined shield and brace plates positioned betweenpairs of said openings, said brace plates lapping over and extending a distance from at least one side of the frame to form shields for auxiliary condensers adapted to be mounted on insulators carried by said lugs and a metal cover fitting over the entire frame, being positioned on the end of said shield plates.

lln testimony whereof, I affix my signature.

STANLEY S. CRAMER. 

